Toenail trauma

The patient’s initial injury was probably a subungual hematoma, which can take 12 to 18 months to resolve (the time it takes for a new toenail to grow). However, the precipitating trauma likely created an opportunity for fungal elements to invade the nail plate, resulting in the current complaint of superficial onychomycosis.

Onychomycosis is a frequently seen condition with increasing prevalence in older patients. It has several clinical presentations: Superficial onychomycosis manifests with chalky white changes on the surface of the nail. Distal subungual onychomycosis develops at the distal aspect of the nail with thickening and subungual debris. Proximal subungual onychomycosis occurs in the proximal aspect of the nail.

Although often asymptomatic, onychomycosis can cause thickening of the nails and development of subsequent deformity or pincer nails (which painfully “pinch” the underlying skin). It is especially concerning in patients with diabetes or peripheral neuropathy, in whom the abnormal thickness and shape of the nails can lead to microtrauma at the proximal and lateral attachments of the nail. These patients have an increased risk of secondary infection, possible complications, and even, for some, amputation.

If the patient is asymptomatic, and does not have diabetes, neuropathy, or other risk factors, treatment is not required. For those who would benefit from treatment, it is usually safe and inexpensive with the current generation of oral antifungal medications.

Some recommend confirmatory testing before treatment intiation,¹ but the low adverse effect profile of terbinafine and its current cost below $10/month² make empiric treatment safe and cost effective in most cases.³ If needed, and with access to microscopy, a potassium hydroxide (KOH) prep can be performed on scrapings from the affected portions of the nail. If that is not available, scrapings or clippings can be sent to the lab for KOH and periodic acid-Schiff staining.

The US Food and Drug Administration previously recommended follow-up liver enzyme tests if terbinafine is used for more than 6 weeks. (Fingernails require only 6 weeks of treatment, but toenails grow more slowly and require 12 weeks of treatment.) However, research has demonstrated that hepatotoxicity risk is extremely low and transaminase elevations are rare.⁴ In the rare cases that liver dysfunction has occurred, patients developed symptoms of jaundice, malaise, dark urine, or pruritis.⁴

This patient was counseled regarding the fungal nature of onychomycosis and the general safety of a 90-day course of oral terbinafine 250 mg/d—provided he did not have underlying liver or kidney disease or leukopenia. He reported that he had not had any blood work performed in the past year but was due for his annual wellness evaluation, at which he would discuss his overall health with his primary care provider, obtain baseline blood testing, and determine whether to proceed with treatment. He was advised that if, after starting treatment, he developed any symptoms of jaundice, dark urine, or other difficulties, he should report them to his care team.

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Photo courtesy of Daniel Stulberg, MD. Text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.

The patient’s initial injury was probably a subungual hematoma, which can take 12 to 18 months to resolve (the time it takes for a new toenail to grow). However, the precipitating trauma likely created an opportunity for fungal elements to invade the nail plate, resulting in the current complaint of superficial onychomycosis.

Onychomycosis is a frequently seen condition with increasing prevalence in older patients. It has several clinical presentations: Superficial onychomycosis manifests with chalky white changes on the surface of the nail. Distal subungual onychomycosis develops at the distal aspect of the nail with thickening and subungual debris. Proximal subungual onychomycosis occurs in the proximal aspect of the nail.

Although often asymptomatic, onychomycosis can cause thickening of the nails and development of subsequent deformity or pincer nails (which painfully “pinch” the underlying skin). It is especially concerning in patients with diabetes or peripheral neuropathy, in whom the abnormal thickness and shape of the nails can lead to microtrauma at the proximal and lateral attachments of the nail. These patients have an increased risk of secondary infection, possible complications, and even, for some, amputation.

If the patient is asymptomatic, and does not have diabetes, neuropathy, or other risk factors, treatment is not required. For those who would benefit from treatment, it is usually safe and inexpensive with the current generation of oral antifungal medications.

Some recommend confirmatory testing before treatment intiation,¹ but the low adverse effect profile of terbinafine and its current cost below $10/month² make empiric treatment safe and cost effective in most cases.³ If needed, and with access to microscopy, a potassium hydroxide (KOH) prep can be performed on scrapings from the affected portions of the nail. If that is not available, scrapings or clippings can be sent to the lab for KOH and periodic acid-Schiff staining.

The US Food and Drug Administration previously recommended follow-up liver enzyme tests if terbinafine is used for more than 6 weeks. (Fingernails require only 6 weeks of treatment, but toenails grow more slowly and require 12 weeks of treatment.) However, research has demonstrated that hepatotoxicity risk is extremely low and transaminase elevations are rare.⁴ In the rare cases that liver dysfunction has occurred, patients developed symptoms of jaundice, malaise, dark urine, or pruritis.⁴

This patient was counseled regarding the fungal nature of onychomycosis and the general safety of a 90-day course of oral terbinafine 250 mg/d—provided he did not have underlying liver or kidney disease or leukopenia. He reported that he had not had any blood work performed in the past year but was due for his annual wellness evaluation, at which he would discuss his overall health with his primary care provider, obtain baseline blood testing, and determine whether to proceed with treatment. He was advised that if, after starting treatment, he developed any symptoms of jaundice, dark urine, or other difficulties, he should report them to his care team.

‌

Photo courtesy of Daniel Stulberg, MD. Text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.

The patient’s initial injury was probably a subungual hematoma, which can take 12 to 18 months to resolve (the time it takes for a new toenail to grow). However, the precipitating trauma likely created an opportunity for fungal elements to invade the nail plate, resulting in the current complaint of superficial onychomycosis.

Onychomycosis is a frequently seen condition with increasing prevalence in older patients. It has several clinical presentations: Superficial onychomycosis manifests with chalky white changes on the surface of the nail. Distal subungual onychomycosis develops at the distal aspect of the nail with thickening and subungual debris. Proximal subungual onychomycosis occurs in the proximal aspect of the nail.

Although often asymptomatic, onychomycosis can cause thickening of the nails and development of subsequent deformity or pincer nails (which painfully “pinch” the underlying skin). It is especially concerning in patients with diabetes or peripheral neuropathy, in whom the abnormal thickness and shape of the nails can lead to microtrauma at the proximal and lateral attachments of the nail. These patients have an increased risk of secondary infection, possible complications, and even, for some, amputation.

If the patient is asymptomatic, and does not have diabetes, neuropathy, or other risk factors, treatment is not required. For those who would benefit from treatment, it is usually safe and inexpensive with the current generation of oral antifungal medications.

Some recommend confirmatory testing before treatment intiation,¹ but the low adverse effect profile of terbinafine and its current cost below $10/month² make empiric treatment safe and cost effective in most cases.³ If needed, and with access to microscopy, a potassium hydroxide (KOH) prep can be performed on scrapings from the affected portions of the nail. If that is not available, scrapings or clippings can be sent to the lab for KOH and periodic acid-Schiff staining.

The US Food and Drug Administration previously recommended follow-up liver enzyme tests if terbinafine is used for more than 6 weeks. (Fingernails require only 6 weeks of treatment, but toenails grow more slowly and require 12 weeks of treatment.) However, research has demonstrated that hepatotoxicity risk is extremely low and transaminase elevations are rare.⁴ In the rare cases that liver dysfunction has occurred, patients developed symptoms of jaundice, malaise, dark urine, or pruritis.⁴

This patient was counseled regarding the fungal nature of onychomycosis and the general safety of a 90-day course of oral terbinafine 250 mg/d—provided he did not have underlying liver or kidney disease or leukopenia. He reported that he had not had any blood work performed in the past year but was due for his annual wellness evaluation, at which he would discuss his overall health with his primary care provider, obtain baseline blood testing, and determine whether to proceed with treatment. He was advised that if, after starting treatment, he developed any symptoms of jaundice, dark urine, or other difficulties, he should report them to his care team.

‌

Photo courtesy of Daniel Stulberg, MD. Text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.